Suction couch roll device



July 28, 1959 R. WELLS 2,895,710

SUCTION COUCH ROLL DEVICE Filed Oct. 16', 1956 INVENT OR Boyer WsZZs BY KHLL. w-fi-TZcns ATTORNEY 2,89 ,710 SUCTION COUCH ROLL DEVICE Roger Wells, Plattshurg, N.Y., assignor to Diamond Gardner Corporation, a corporation 'of Delaware Application October 16, 1956, Serial No. 616,162 7 Claims. (Cl. 162-371) This invention relates to couch rolls, and more particularly to suction rolls or cylinders of machines for making paper or sheets of molded pulp, and the like.

At one stage in the manufacture of sheets of paper or molded pulp, and the like, the sheets of 'wet pulp are advanced continuously over a rotatably mounted cylindrical roll, known as a couch roll, which is connected internally to a source of suction and has perfora tions formed in its periphery through which excess liquid is sucked from the advancing sheets of wet pulp. The sheets of wet pulp are usually supported upon an endless pervious band made of wire or cloth passing around the couch roll. Suction is'applied to the sheets of wet pulp from the interior of the roll as the sheets advance around a predetermined portion of the periphery of the roll, and then compressed air is applied from the interior of the roll to blow the sheets off the roll. The couch roll is provided with one or more longitudinal drainage channels for carrying away the excess liquid sucked from the wet pulp sheets. However, in the couch rolls employed heretofore, some of the excess liquid was blown back out-through the perforations in the roll during the subsequent application of the compressed air for blowing off the pulp sheets. The excess liquid blown back onto the pulp sheets being removed from the couch roll frequently damaged the sheets, created undesirable blemishes thereon, or caused warpage due to lack of uniformity in drying characteristics, resulting in a defective product.

An object of the present invention is to provide a new and improved couch roll for making paper, or sheets of molded pulp, and the like.

Another object of the invention is to provide couch rolls with means for preventing any excess liquid from being blown upon sheets of pulp being removed therefrom.

Still another object of the invention is to provide a new and improved drainage trap for couch rolls.

Other objects and the nature and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, wherein:

Fig. l is a vertical sectional view of a couch embodying the invention; and

Fig. 2 is an enlarged vertical sectional view of a portion of the roll shown in Fig. 1.

In a manner well known in the art of manufacturing pulp and paper products, continuous sheets or slabs of paper or molded pulp may be formed by depositing wet pulp fibers upon a moving endless band made of a pervious material, such as wire or cloth, spreading the wet pulp uniformly across the band to form a sheet, advancing the sheet of wet pulp on the band between initial compression rolls, and then advancing the band around a couch roll connected internally to a source of suction which extracts excess liquid from the wet pulp. A blast of compressed air may be employed to blow the pulp sheet ofi the couch roll. Subsequently,

roll

the pulp sheet may be advanced between final compres-. sion rolls, through dryers, and thence past cutters, if desired.

Referring to the drawings, Fig. 1 shows an endless pervious band 10, of the type previously described, designed to advance across a series of supporting table rolls 12-12, and thence around a cylindrical couch roll 14, which is rotatable in a clockwise direction, as

, indicated by the arrow. Between the points marked A and B, at which points the band 10 contacts the roll \14 tangentially, the band. 10 advances around approxiinately half of the periphery of the roll 14 in snug engagement therewith. A fixed vacuum chamber 16, which also. functions as a drainage channel, extends longitudinally through the roll 14 between opposite ends thereof and is connected. to an external source of suction (not shown). The vacuum chamber 16 applies suction to a portion of the periphery of the roll 14 between the point A and a point marked C. A fixed pressure chamber 18, mounted adjacent to the yacuum chamber 16, extends longitudinally through the roll 14 between opposite ends thereof, and is connected to an external source of compressed air (not shown). The pressure chamber 18 applies air pressure to a small portion of the periphery of the roll 14 between the point C and a point designated D. During rotation of the roll 14 and the advancement of the band 10 therearound, the excess liquid in the sheet of wet pulp carried on the band 10 is sucked out and drained off through the vacuum chamber 16, and then the partially dried sheet of pulp is blown off the band 10 by the air pressure in the chamber 18.

As is best shown in Fig. 2, the periphery of the couch roll 14 is provided with a plurality of radial perforations 20-20 spaced at uniform intervals over the entire area thereof. The excess liquid sucked from the wet pulp by the vacuum in the chamber 16 flows inwardly through the perforations 20-20,' and the compressed air applied from the chamber 18 blows outwardly through the same perforations. In the couch rolls known prior to the present invention, at times some of the excess liquid which had been sucked inwardly through the perforations in the roll, and which clings to the inner walls thereof or to any crevices or recesses formed in the interior of the roll, is blown back out through the perforations during the subsequent application of the compressed air. Any liquid blown out through the perforations in this manner blows upon the sheet of pulp being ejected by the blast of compressed air. Since at this stage of its formation the pulp sheet is still damp and pliable, it is readily susceptible to damage from blowing liquid. Furthermore, the liquid blown back onto the pulp sheet frequently created unsightly blemishes, or warpage caused by sack of uniformity in drying characteristics.

In accordance with the present invention, the possibility of having any residual liquid blown out through the perforations 20--20 in the couch roll 14- is prevented by providing individual drainage traps in the interior of the roll around each of the perforations. For this purpose, a plurality of inwardly projecting standpipes 22-22 are in serted into the perforations 20-20 or are formed integral therewith, one of the standpipes 2222 being mounted or formed in each of the perforations 20--20 over the entire periphery of the couch roll 14. The standpipes 2222 may be removably threaded or otherwise se curely fitted within or formed integral with the perforations 20-20. As is best shown in Fig. 2, the standpipes 2222 are flush with the exterior surface of the couch roll 14, but they project radially inwardly a substantial distance from the interior surface ofthe roll, which distance is .suflicient to trap the maximum quantity of residual liquid normally expected to collect within the interior of the roll 14.

Due to the presence of the inwardly projecting standpipes 2222, special precaution must be taken to pro vide air-tight seals at the junctures of the side walls of the fixed chambers 16 and 18 with the inner periphery of the roll 14, in order to maintain a vacuum and a pressure, respectively, within these chambers during rotation of the roll 14 therepast. A side wall 24 of the chamber 16extends approximately radially toward the point A on the periphery of the roll 14. At the opposite side of the chamber 16 a wall 25 disposed approximately in radial alignment with the point C serves as a common side wall for the chambers 16 and 18. The chamber 18 is also provided with a side wall 26 near the point D. The three side walls 24, 25 and 26 project toward the inner periphery of the roll 14 from two bottom walls 27 and 28 of the chambers 16 and 18, respectively. These side walls may be disposed in other ways than radially, and the shape of the chambers 16 and 18 may be varied the inner periphery of the roll' for forming air-tight as desired, provided that the chambers cover a suflicient arcuate portion of the inner periphery of the couch roll 14. a

A plurality of soft resilient rolls 30, 31 and 32 are mounted rotatably on thetops of the respective walls 24, 25 and 26. Preferably, the rolls 30, 31 and 32 are made of smooth-surfaced sponge rubber. As is best shown in Fig. 2, wherein the roll 31 is illustrated, each of these soft resilient rolls is capable of indenting sufficiently to cover the ends of a plurality of rows of the standpipes 22-22, and at the same time press into sealing engagement with the inner periphery of the couch roll 14 between the covered standpipes. A plurality of doctor blades 34, 35 and 36 may be mounted on the tops of the respective side walls 24, 25 and 26 in sealing engagement with the resilient rolls 30, 31 and 32. However, the doctor blades 34, 35 and 36 are not absolutely necessary, provided the resilient rolls 30,31 and 32 are in sealing engagement with the tops of the side walls 24, 25 and 26 of the chambers 16 and 18.

Apparatus embodying the invention effectively prevents any residual liquid sucked into the couch roll from being blown back out upon sheets of pulp being removed therefrom. This is accomplished by providing the standpipes 2222 to form individual drainage traps in the interior of the couch roll 14 around each of the perforations -20 therein. During rotation of the roll 14, the perforations 20-20 therein are advanced successively past the chambers 16 and 18 and are subjected thereby to suction and air pressure, respectively, in succession. The standpipes 2222 mounted in the perforations 20-20 trap any residual liquid clinging to the inner periphery of the roll 14 within the chamber 16, and prevent this liquid from being blown back out during the subsequent application of the air pressure in the chamber 18. The soft resilient rolls 30, 31 and 32 mounted rotatably on the tops of the side walls of the chambers 16 and 18 form air-tight seals with the inner periphery of the rotating couch roll 14 despite the presence of the standpipes 2222 projecting therefrom.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is: p

l. A couch roll, comprising a rotatable cylindrical roll having a plurality of radial perforations at intervals on its periphery, a fixed vacuum chamber mounted within the roll for applying suction to a portion of the periphery of the roll during its rotation to suck excess liquid from a sheet of wet pulp passing therearound, a fixed pressure chamber mounted within the roll adjacent to the vacuum chamber for applying a blast of compressed air to a portion of the periphery of the roll to blow the sheet of pulp 011 the roll, a plurality of standseals therebetween and for sealingly covering the inner ends of the standpipes as they are advanced therepast during rotation of the couch roll.

2. A couch roll, comprising a rotatable cylindrical roll having a plurality of radial perforations at intervals on its periphery, a fixed vacuum chamber mounted within the roll for applying suction to a portion of the periphery of the roll during its rotation to suck excess liquid from a sheet of wet pulp passing therearound, a

fixed pressure chamber mounted within the roll adjacent to the vacuum chamber for applying a blast of compressed air to a portion of the periphery of the roll to blow the sheet of pulp olf the roll, a plurality of standpipes mounted one for each in the perforations for preventing residual liquid from being blown out of the roll by the blast of compressed air, said standpipes being flush with the outer periphery of the roll and projecting radially inwardly from the inner. periphery thereof a distance sufiicient to trap the maximum quantity of residual liquid expected to collect within'the roll, and a plurality of resilient members mounted at the juncture of the chambers with the inner periphery of the roll for forming air-tight seals therebetween and for sealingly covering the inner ends of the standpipes as they are advanced therepast during rotation of the couch roll.

3. A couch roll, comprising a rotatable cylindrical roll having a plurality of radial perforations at equal intervals over its entire periphery, a fixed vacuum chamber extending longitudinally through the interior of the roll and communicating with a portion of its inner periphery for sucking excess liquid through the perforations therein from a sheet of wet pulp carried on its outer periphery, a fixed pressure chamber extending longitudinally through the interior of the roll adjacent to the vacuum chamber and communicating with another portion of the inner periphery of the roll for subjecting the perforations to a blast of compressed air to blow the sheet of pulp off the roll after its suction treatment, a plurality of standpipes mounted in the perforations in the interior of-the roll to form individual drainage traps for preventing residual liquid from being blown out through the perforations by the subsequent blast of compressed air, one of said standpipes being mounted in each of the perforations flush with the outer periphery of the roll and projecting radially inwardly 1 a distance sufiicient to trap the maximum quantity of residual liquid expected to collect within the roll, and a plurality of resilient indentable sealing members mounted at the juncture of the chambers with the inner periphery of the roll for forming air-tight seals there- 'between and for sealingly covering the inner ends of the standpipes as they are advanced therepast during rotation of the couch roll.

4. A couch roll, comprising a rotatable cylindrical roll having a plurality of radial perforations at equal intervals over its entire periphery, a fixed vacuum chamber extending longitudinally through the interior of the roll and communicating with a portion of its inner periphery for sucking excess liquid through the perforations therein from a sheet of wet pulp carried on its outer periphery, a fixed pressure chamber extending longitudinally through the interior of the-roll adjacent to the vacuum chamber and communicating with another porsheet of pulp off the roll after its suction treatment, a plurality of standpipes mounted in the perforations in the interior of the roll to form individual drainage traps for preventing residual liquid from being blown out through the perforations by the subsequent blast of compressed air, one of said standpipes being mounted in each of the perforations flush with the outer periphery of the roll and projecting radially inwardly a distance sufiicient to trap the maximum quantity of residual liquid expected to collect within the roll, and a plurality of resilient rolls mounted rotatably at the juncture of the chambers with the inner periphery of the couch roll to form air-tight seals therewith.

5. A couch roll, comprising a rotatable cylindrical roll having a plurality of radial perforations at equal intervals over its entire periphery, a fixed vacuum chamber extending longitudinally through the interior of the roll and covering a portion of its inner periphery for sucking excess liquid through the perforations therein from a sheet of wet pulp carried on its outer periphery, a fixed pressure chamber extending longitudinally through the interior of the roll adjacent to the vacuum chamber and covering another portion of the inner periphery of the roll for subjecting the perforations to a blast of compressed air to blow the sheet of pulp off the roll after its suction treatment, said chambers having side walls extending toward the inner periphery of the couch roll, a plurality of standpipes mounted in the perforations in the interior of the roll to form individual drainage traps for preventing residual liquid from being blown out through the perforations by the subsequent blast of compressed air, one of said standpipes being mounted in each of the perforations flush with the outer periphery of the roll and projecting radially inwardly a distance sufficient to trap the maximum quantity of residual liquid expected to collect within the roll, and a plurality of soft resilient rolls mounted rotatably on the tops of the side walls of the chambers and forming air-tight seals between said walls and the inner periphery of the couch roll.

6. A couch roll, comprising a rotatable cylindrical roll having a plurality of radial perforations at equal intervals over its entire periphery, a fixed vacuum chamber extending longitudinally through the interior of the roll and covering a portion of its inner periphery for suckingexcess liquid through the perforations therein from a sheet of wet pulp carried on its outer periphery, a fixed pressure chamber extending longitudinally through the interior of the roll adjacent to the vacuum chamber and covering another portion of the inner periphery of the roll for subjecting the perforations to a blast of compressed air to blow the sheet of pulp off the roll after its suction treatment, said chambers having side walls extending toward the inner periphery of the couch roll, a plurality of standpipes mounted in the perforations in the interior of the roll to form individual drainage traps for preventing residual liquid from being blown out through the perforations by the subsequent blast of compressed air, one of said standpipes being mounted in each of the perforations flush with the outer periphery of the roll and projecting radially inwardly a distance sufiicient to trap the maximum quantity of residual liquid expected to collect within the roll, and a plurality of soft resilient rolls composed of smooth-surfaced sponge rubber mounted rotatably on the tops of the side walls of the chambers in air-tight sealing engagement with the inner periphery of the couch roll and with the standpipes therein, and a plurality of doctor blades mounted on the tops of said walls in air-tight engagement with the rubber rolls.

7. A couch roll-comprising a rotatable cylindrical roll having a plurality of perforations at intervals on its periphery and adapted to have a sheet of wet pulp passed therearound to extract excess liquid therefrom, a fixed vacuum chamber extending longitudinally through the interior of the roll and covering a portion of its inner periphery for sucking excess liquid from a sheet of wet pulp carried on its outer periphery, a fixed pressure chamber extending longitudinally through the interior of the roll adjacent to the vacuum chamber for applying a blast of compressed air to blow the sheet of pulp 08 the roll following its suction treatment, said chambers having side walls extending radially toward the inner periphery of the roll, a plurality of soft resilient rolls mounted rotatably at thev tops of said side walls and forming seals between said side walls and the inner periphery of the couch roll, and a plurality of standpipes mounted in the perforations in the couch roll for forming drainage traps to prevent excess liquid from being blown out through the perforations by the blast of compressed air, one of said standpipes being mounted in each of the perforations flush with the outer periphery of the roll and projecting radially inwardly a distance suflicient to trap any residual liquid within the couch roll, 'said soft resilient rolls being capable of indenting sufiiciently to cover the projecting ends of the standpipes while also pressing into sealing engagement with the inner periphery of the couch roll between the standpipes.

A References Cited in the file of this patent UNITED STATES PATENTS 1,581,656 Monaghan Apr. 20, 1926 2,006,519 Standley July 2, 1935 2,107,812 Berry et al. Feb. 8, 1938 2,696,149 Hornbostel Dec. 7, 1954 2,780,967 Dearden Feb. 12, 1957 FOREIGN PATENTS 633,324 Germany July 24, 1936 

